Firesafe vs firetested valves 4

[MIKEY101DOH]

Can someone confirm or correct my understanding of the terms firetested and firesafe;
A firetested valve must be operable after the test but need not be seal tight whereas a firesafe valve must fully seal.
The reason for my question is a client is requesting a rubber lined firesafe butterfly valve and i need to be 100% certain of the facts before i tell him such an animal does not exist.

 

[JLSeagull]

API 607
For soft-seated valves up to DN 100 or NPS 4 and pressure ratings up to PN 40, Class 300, use two flame
environment thermocouples, two body thermocouples and calorimeter cubes as shown in Figure 3.

 

[terje61]

Hello Mikey,

I am not fully sure, but I always explained it as follows:

In order to say that your valve is fire safe, you must perform a test. According to API 607 / API 6FA / EN ISO 10497 or others.

When your valve passes the fire safe test it will qualify for the tested size and rating. Plus 1 rating higher and all valves up to twice the size. So a 4" Class 300 test valve will qualify all valve sizes/ratings between 4" Class 300 and 8" class 600.

Using the above stated example the answer to your question would be:
- The certified fire safe valves are all valves between 4" Class 300 and 8" class 600
- The fire safe tested valve is only the 4" Class 300 valve.

Anybody is welcome to correct me in case I have misinterpreted this.

Best regards,
Terje

 

[JLSeagull]

I would hesitate before stating general facts pertaining to rubber-lined fire-safe valves. However API 607 accommodates soft-seated valves. That was just one paragraph of several that mentioned soft seats. Consider sending the inquiry to multiple valve suppliers specifying the material and fire safe requirement to see their responses.

 

[JimCasey]

I see valves marketed as "fire-safe" and "Fire-sealed"
Fire-safe valves do not leak to the environment and they have metallic seating elements that limit leakage through the valve after the soft-seats are destroyed by the heat of the fire. You can get fire-safe High-Performance butterfly valves that have a backup metallic seat that takes over after the primary TFE ring goes away.

Fire-sealed valves can leak through after a fire but they don't leak to the environment. A rubber-lined butterfly valve would need a graphite stem seal to do this.
This is not impossible but unlikely and probably more expensive than using a HPBV. Rubber-lined butterfly valves usually don't have packing, the liner has an interference fit with the shaft and it seals there. Also RLBVs have almost universally, (unwetted) cast Iron bodies that can't take fire-test heat. You'd be looking for an extremely special RLBV where you could get a firesafe HPBV just by checking an option box on the order form. See the Durco BigMax BX2000 as example.

 

[gerhardl]

To Jim Casey: good information!

To Terje 61: Also according to my knowledge.

To Mikey101DOH:
Further to Terje61's information. Be very precise in what is actually required from the end user.

1. If it is a firesafe certified valve, this is as Terje61 says either a valve of size and pressure class that directly has been tested, test accepted by some accredited institute, certificate available and valid, or nearest size (allowed within parameters given in test procedure) , again with valid certificate available!

2. A valve with firsafe design is very often a way of telling the buyer that : this valve has not been tested or have a valid certificate, but we believe we know how to make such a construction.

If valves are constructed under point 2, you will have a very varied quality range. Producers will range from fully qualified producers with long experience with other ranges of valves tested with certifications, to newcomers trying to come into the market or pure copied constructions.

Wether a valve from the point 2 range qualifies is again up to end-users.

Experienced end users will normally have some producers and ranges/types of valves listed as accepted or preferred, type 1 and/or 2.